Our Research & Scoring Methodology
How NutriDupe calculates active-ingredient equivalence, bioavailability ratings, and price-per-serving transparency.
What Defines a NutriDupe?
A NutriDupe is NOT a cheap knock-off or unverified counterfeit. Every alternative listed must meet three non-negotiable standards:
cGMP-Certified Facility
Manufactured under current Good Manufacturing Practice regulations enforced by the FDA.
FDA-Registered Facility
Produced in a facility registered with the U.S. Food and Drug Administration.
Third-Party Purity Verification
Verified by NSF, USP, Informed-Sport, or accompanied by a verifiable Certificate of Analysis (CoA).
The 50/30/20 Equivalence Formula
Every NutriDupe comparison score is calculated using a transparent, weighted formula that prioritizes what matters most for clinical equivalence.
Equivalence Score = (50% × Active Overlap) + (30% × Dosage Precision) + (20% × Bioavailability Quality)
Active Ingredient Overlap
50% WeightEvaluates raw active compound presence while excluding fillers, synthetic binders, and inactive excipients. We compare the complete list of active ingredients in the benchmark product against the dupe, calculating the percentage of shared actives by both count and clinical relevance.
Dosage Precision
30% WeightCompares active milligrams per serving against the benchmark's label claims or established clinical study thresholds. A dupe with dosages within 10% of the benchmark receives full credit; wider deviations are penalized proportionally to ensure therapeutic equivalence.
Bioavailability & Chemical Quality
20% WeightGrades compound absorption based on chemical form. Grade 5 is awarded for chelated or methylated forms (e.g., Magnesium Glycinate, Methylcobalamin). Grades descend to Grade 1 for low-absorption forms like oxides (e.g., Magnesium Oxide), which have documented bioavailability as low as 4%.
| Grade | Form Quality | Examples | Absorption |
|---|---|---|---|
| 5 | Chelated / Methylated | Magnesium Glycinate, Methylcobalamin, P5P | Excellent |
| 4 | Coenzymated / Active | 5-MTHF Folate, CoQ10 Ubiquinol | Very Good |
| 3 | Standard / Citrate | Creatine Monohydrate, Calcium Citrate | Good |
| 2 | Bound / Complex | Zinc Gluconate, Magnesium Citrate | Moderate |
| 1 | Oxide / Low-grade | Magnesium Oxide, Zinc Oxide | Poor (as low as 4%) |
Cost Calculation Transparency
Price-per-serving is the single most important metric for true cost comparison. We calculate it using a straightforward, auditable formula.
Cost Per Serving = Retail Package Price / Servings Per Container
Editorial Independence
Our scoring formula is applied identically to every product, regardless of affiliate status. Affiliate partnerships do not influence equivalence scores, bioavailability grades, or cost calculations. All scores are derived from publicly available label data and peer-reviewed clinical literature.